1. Field of the Invention
This invention relates to a flashlight, and in particular to a flashlight including a conventional light source such as an incandescent bulb, krypton, halogen, xenon, or mercury vapor lamp, fluorescent tube, cold cathode tube, or light emitting diode, and at least one electro-luminescent lighting element, so that the flashlight can emit light of different intensities and power consumption and therefore serve not only as a conventional flashlight but also, by way of example, as a night light, warning beacon, or light stick.
2. Discussion of Related Art
Conventionally, flashlights have included only a single light source and are not convenient, even with the inclusion of a tile angle lens or the like, for such applications as area illumination. In addition, even if the conventional flashlight could be used for area illumination, the power consumption of the conventional flashlight prevents it from being used for such purposes for an extended period of time. Essentially, in the conventional flashlight, a tradeoff must be made between providing a high intensity beam and reducing power consumption. The present invention modifies the conventional flashlight by adding an electro-luminescent lighting arrangement to a flashlight that also includes a conventional light source, thus enabling the flashlight to provide both high intensity lighting and lighting at lower intensities with lower power consumption.
Electro-luminescent lighting arrangements have been proposed for use in a variety of specific contexts, including illumination of footwear, headwear, backpacks, safety guides, moving objects, flying objects, containers, timepieces, and audio equipment, because of their flexibility and low power consumption, and their relative brightness, color choice, and wide viewing angle in comparison with other low power consumption devices such as LEDs.
In U.S. Pat. No. 5,806,960, incorporated herein by reference, and its continuation, U.S. patent application Ser. No. 08/998,767, filed Dec. 29, 1997, the Inventor proposes modification of a conventional safety light or flashlight by substituting an electro-luminescent element for the traditional light source to obtain such advantages as decreased power consumption and increased design flexibility with respect to color choice, brightness, lighting effects such as flashing or sequencing, and decorative non-illuminated effects. Although the brightness of a flashlight that uses electro-luminescent elements instead of the conventional light source may be sufficient for many applications, electro-luminescent elements in general are not as bright as incandescent, krypton, halogen, or similar bulbs of the type conventionally used in flashlights, which are intended to focus a relatively high intensity light beam on a relatively small area. As a result, the present invention proposes to combine a conventional high intensity flashlight with a lower power, lower intensity lighting arrangement that can nevertheless be used in wide area or surface illumination applications for which a conventional flashlight is ill suited.
A concept similar to that of the present invention is disclosed in copending U.S. patent application Ser. No. 09/158,503, filed Sep. 18, 1993 and also incorporated herein by reference. In this copending application, the Inventor proposes to combine an electro-luminescent element with at least one other type of light source to provide different light qualities for different conditions. The present invention applies the concept described in U.S. patent application Ser. No. 09/158,503 to the specific context of flashlights, and in particular to flashlights having a conventional light source such as an incandescent bulb, krypton, xenon, or halogen bulb, mercury vapor lamp, fluorescent tube, cold cathode tube, light emitting diode, or other lighting element suitable for use in flashlights.
A flashlight having two different types of light sources is described in U.S. Pat. No. 5,806,961. The primary light source is a conventional lighting element while the second light source is said to provide a night light function but is powered by DC current from a rechargeable battery. Unlike the electro-luminescent elements of the present invention, which can be driven directly by an AC power supply, because the second light source of U.S. Pat. No. 5,806,961 is DC powered, relatively expensive driver circuitry is required and yet the disclosed circuitry provides none of the enhanced lighting effects described above. An LED of the type described in this patent as a suitable second light source is too dim and has too narrow a viewing angle to provide effective surface or area illumination, particularly in relation to the space occupied by the LED and support structure (a minimum area of 10 mm.times.3 mm is generally required). As a result, the flashlight of U.S. Pat. No. 5,806,961 is not practical for use as a secondary source of surface/area illumination, and a need still exists for a device that serves both as a flashlight to provide high intensity lighting and as a source of wide area illumination at lower intensities and power levels.